1. Field of the Invention
The present invention relates to the field of mechanical analog or equivalents to simple binary calculators, and more particularly to small mechanical apparatus for performing binary addition and substraction.
2. Discussion of the Prior Art
The lives of nearly everyone in this country are affected at least to some extent by computers. For example, our income taxes are audited by computers and many of the items and services we purchase are billed by computers. Prices of small, hand-held or desk top electronic calculators have now decreased to the extent that they are owned by large numbers of people, and have substantially replaced previously used calculators such as slide rules. These small electronic calculators, virtually all of the binary type, are being increasingly used in schools, even in the elementary grades. This latter use is much to the dissatisfaction of many who believe that even with the availability of computers, the basics of arithmetic should be learned, or at least basic operational principles of the binary system used by the computers in their performance of simple and complex operations should be taught.
For this reason, various types of mechanical analogs or equivalents of simple electronic binary calculators have been disclosed to enable visualization and easy learning or teaching of simple binary operations. Such disclosures include those of Libbey, Lieberman et al., Godfrey, Divilbiss and Youngman (U.S. Pat. Nos. 3,006,082; 3,273,794; 3,390,471; 3,403,459 and 3,747,844). Use of mechanical apparatus corresponding to simple electronic binary functions is made possible by characteristics of the binary or radex two system in which all numbers are represented by a series of 0's and 1's, according to the simple binary rule that "1 plus 1 equals 0, carry 1". As an example, in binary form, the number 1 is represented by 0001, the number 2 by 0010, the number 3 by 0011 and the number 4 by 0100.
Although most conventional or arabic numbers require more digits in the binary system, the 0's and 1's are much easier to operate on in the computer. This is because the 0's and 1's can be represented by an off and on states of electronic switches or by either of bistable states of simple flip-flop circuit elements. It is for this same reason that mechanical equivalents can easily be constructed; equivalents in which electrical or electronic switches are replaced by mechanical gates which are acted upon by, for example, balls instead of electronic impulses.
Thus, such disclosures as above referred to employ many pivoting elements which can deflect a ball in either of two directions depending upon whether the element has or has not just previously been acted upon by another ball. The advantages of such mechanical apparatus is that a user may visually follow the computers decision making process and thereby gain an insight into computer design and operation. In an actual electronic computer the operations proceed at such rapid rates that even were lights indicative of the operations provided, the steps could not be followed. But in a mechanical equivalent, the operation can not only be seen, but it is also slowed down to an extent that it can, to some extent, be followed and understood.
Heretofore disclosed mechanical analogs or equivalents to simple electronic binary functions have, however, because they employ numbers of pivoting members, been relatively complex, subject to breaking or malfunction and have been comparatively costly to produce and purchase. They are, for example, generally too costly for one to be provided to each student in a class or even to provide several for each classroom where their use may be desired.
In addition, after balls representing binary 1's are introduced into such mechanical apparatus, the operation generally proceeds in an automatic manner and cannot easily be stopped or slowed for examination of individual steps as may be necessary for explanation and understanding.
For these and other reasons, simpler, less costly and more versatile mechanical binary apparatus are required to fulfill the need for teaching and learning simple binary operations.